The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Halbach array systems and other permanent magnet configurations have been used for many applications, such as coupling systems (e.g., U.S. Pat. No. 6,841,910 to Gery and U.S. Pat. Pub. 2013/0113317 to Englert) and electromagnetic machines that convert mechanical energy to electrical energy. Typical electromagnetic machines have a rotor and a stator. The rotor contains magnets and the stator contains windings to carry the electric current through the coils. While the basic configuration of electromagnetic machines is known, such machines appear to be fairly limited in efficiency.
One example of an electromagnetic machine is U.S. Pat. No. 7,105,979 to Gabrys, which discloses a heteropolar hybrid machine for converting between electrical and mechanical energy. The machine has a rotor that comprises ferromagnetic and permanent magnet poles around its circumference and a stator having a field coil and an armature located in an armature air gap of the rotor. The field coil generates a field coil flux and the permanent magnet poles generate a permanent magnetic flux that both flow through the armature air gap through the ferromagnetic rotor structure to induce AC voltage in multiphase windings of the armature. However, a larger air gap is required between the rotor and stator to place the windings, which may increase the demand of magnetomotive force.
Other examples of known electromagnetic machines can be found in U.S. Pat. No. 8,193,657 to Paluszek and U.S. Pat. No. 8,397,369 to Smith. Unfortunately, known efforts apparently failed to appreciate optimized magnetic flux configurations.
Thus, there is still a need for improved magnetic generators.